IPhone数据库操作代码例子
//database operation
打开数据库
-(BOOL) opendatabase{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:@"mydb.sql"];
NSFileManager *fileManager = [NSFileManager defaultManager];
BOOL find = [fileManager fileExistsAtPath:path];
//找到数据库文件mydb.sql
if (find) {
NSLog(@"Database file have already existed.");
if(sqlite3_open([path UTF8String], &database_) != SQLITE_OK) {
sqlite3_close(database_);
NSLog(@"Error: open database file.");
return NO;
}
return YES;
}
if(sqlite3_open([path UTF8String], &database_) == SQLITE_OK) {
//bFirstCreate_ = YES;
[self createChannelsTable:database_];//在后面实现函数createChannelsTable
return YES;
} else {
sqlite3_close(database_);
NSLog(@"Error: open database file.");
return NO;
}
return NO;
}
创建表
- (BOOL) createChannelsTable:(sqlite3*)db{
char *sql = "CREATE TABLE reports (id integer primary key,stime text,stitle text,scal text,sruntime text)";
sqlite3_stmt *statement;
if(sqlite3_prepare_v2(db, sql, -1, &statement, nil) != SQLITE_OK) {
NSLog(@"Error: failed to prepare statement:create reports table");
return NO;
}
int success = sqlite3_step(statement);
sqlite3_finalize(statement);
if ( success != SQLITE_DONE) {
NSLog(@"Error: failed to dehydrate:CREATE TABLE reports");
return NO;
}
NSLog(@"Create table 'reports' successed.");
return YES;
}
插入表
- (BOOL)insertOneChannel:(NSString*)stime mytitle:(NSString*)stitle mycal:(NSString*)scal myruntime:(NSString*)sruntime
{
sqlite3_stmt *statement;
static char *sql = "INSERT INTO reports (id,stime,stitle,scal,sruntime) VALUES(NULL,?,?,?,?)";
//问号的个数要和(cid,title,imageData,imageLen)里面字段的个数匹配，代表未知的值，将在下面将值和字段关联。
int success = sqlite3_prepare_v2(database_, sql, -1, &statement, NULL);
if (success != SQLITE_OK) {
NSLog(@"Error: failed to insert:channels");
return NO;
}
//这里的数字1，2，3，4代表第几个问号
//sqlite3_bind_text(statement, 1, stime, -1, SQLITE_TRANSIENT);
char *p = [stime cStringUsingEncoding:1];
sqlite3_bind_text(statement, 1, [stime cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);
sqlite3_bind_text(statement, 2, [stitle cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);
sqlite3_bind_text(statement, 3, [scal cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);
sqlite3_bind_text(statement, 4, [sruntime cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);
success = sqlite3_step(statement);
sqlite3_finalize(statement);
if (success == SQLITE_ERROR) {
NSLog(@"Error: failed to insert into the database with message.");
return NO;
}
NSLog(@"Insert One Channel#############:id = _");
return YES;
}
查询表
- (void) getChannels:(NSMutableArray*)fChannels{
sqlite3_stmt *statement = nil;
char *sql = "SELECT * FROM reports";
if (sqlite3_prepare_v2(database_, sql, -1, &statement, NULL) != SQLITE_OK) {
NSLog(@"Error: failed to prepare statement with message:get channels.");
}
//查询结果集中一条一条的遍历所有的记录，这里的数字对应的是列值。
while (sqlite3_step(statement) == SQLITE_ROW) {
//char* cid = (char*)sqlite3_column_text(statement, 1);
char* stime = (char*)sqlite3_column_text(statement, 1);
char* stitle =(char*)sqlite3_column_text(statement, 2);
char* scal = (char*)sqlite3_column_text(statement, 3);
char* sruntime= (char*)sqlite3_column_text(statement, 4);
//NSString *tmp = [NSString stringWithCString:stitle encoding:1];
myreportitem* ri = [[myreportitem alloc] init];
ri.mytime = [NSString stringWithCString:stime encoding:1];
ri.mytitle = [NSString stringWithCString:stitle encoding:1];
ri.mycal = [NSString stringWithCString:scal encoding:1];
ri.myruntime = [NSString stringWithCString:sruntime encoding:1];
[fChannels addObject:ri];
[ri release];
}
sqlite3_finalize(statement);
}
删除记录
- (void)doClearReport: {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:@"mydb.sql"];
NSFileManager *fileManager = [NSFileManager defaultManager];
BOOL find = [fileManager fileExistsAtPath:path];
//找到数据库文件mydb.sql
if (find) {
NSLog(@"Database file have already existed.");
if(sqlite3_open([path UTF8String], &database_) != SQLITE_OK) {
sqlite3_close(database_);
NSLog(@"Error: open database file.");
return NO;
}
char *sql = "delete from reports";
sqlite3_stmt *statement;
if(sqlite3_prepare_v2(database_, sql, -1, &statement, nil) != SQLITE_OK) {
NSLog(@"Error: failed to prepare statement:create reports table");
return NO;
}
int success = sqlite3_step(statement);
sqlite3_finalize(statement);
if ( success != SQLITE_DONE) {
NSLog(@"Error: failed to dehydrate:delete TABLE reports");
return NO;
}
NSLog(@"Create table 'reports' successed.");
sqlite3_close(database_);
}
}
